Corrosion resistant ground shield of processing chamber

ABSTRACT

A substrate support assembly includes a ground shield and a heater that is surrounded by the ground shield. The ground shield includes a plate. In one embodiment, the ground shield is composed of a ceramic body and includes an electrically conductive layer, a first protective layer on the upper surface of the plate. In another embodiment, the ground shield is composed of an electrically conductive body and a first protective layer on the upper surface of the plate.

TECHNICAL FIELD

Embodiments of the present disclosure relate, in general, to a groundshield for a heater that can allow for uniformity in the formation ofbiased plasma, and, in particular, to a ground shield that is resistantto corrosion and/or erosion (e.g., such caused by a plasma environment).

BACKGROUND

In the semiconductor industry, heaters are used to support substratesand to heat those substrates during processing, such as duringdeposition processes and/or etch processes that use plasma. A radiofrequency (RF) field may be introduced to a substrate processingapparatus to facilitate oscillation between the heater and othercomponents of the processing unit, which aids in the use of plasma.Ground shields may be used to help ground the heater to allow forgreater uniformity of a plasma during this processing. Current groundshields are made of aluminum or stainless steel materials, and arecoated with a protective coating that has a coefficient of thermalexpansion (CTE) that is very different from a CTE of the aluminum orstainless steel. Because of the significantly different CTE valuesbetween aluminum or stainless steel materials and traditional protectivecoatings on the ground shield, the protective coating frequently cracks,exposing the aluminum or stainless steel material to a corrosiveenvironment and/or to plasma. This prevents existing ground shields frombeing used in biased, high temperature applications.

SUMMARY

In one embodiment, a ground shield of a processing chamber includes aceramic body comprising a plate and a raised edge extending from anupper surface of the plate. A heater fits within the raised edge on theupper surface of the plate. The ground shield further includes anelectrically conductive layer on at least the upper surface of theplate, and a first protective layer on at least the electricallyconductive layer.

In one embodiment, a substrate support assembly of a processing chamberincludes a heater, and a ground shield comprising a disc-shaped ceramicbody and a shaft that extends from a lower surface of the disc-shapedceramic body. An upper surface of the disc-shaped ceramic body comprisesa raised edge that extends from an upper surface of the disc-shapedceramic body. The heater is disposed on the upper surface of thedisc-shaped ceramic body within the raised edge. The ground shieldfurther includes an electrically conductive layer on at least the uppersurface of the disc-shaped ceramic body, and a first protective layer onat least the electrically conductive layer.

In one embodiment a ground shield of a processing chamber includes anelectrically conductive body including a plate and a raised edgeextending from an upper surface of the plate. A heater fits within theraised edge on the upper surface of the plate. The raised edge includesan edge interior wall, an edge upper surface, and an edge exterior wall.The ground shield further includes a first protective layer on at leastthe upper surface of the plate, and a second protective layer on atleast the first protective layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings in which likereferences indicate similar elements. It should be noted that differentreferences to “an” or “one” embodiment in this disclosure are notnecessarily to the same embodiment, and such references mean at leastone.

FIG. 1 depicts a sectional view of one embodiment of a processingchamber.

FIG. 2 depicts an exploded view of one embodiment of a ground shieldassembly.

FIG. 3A depicts a sectional view of one embodiment of a ceramic groundshield assembly comprising an electrically conductive layer and a firstprotective layer.

FIG. 3B depicts another sectional view of one embodiment of a ceramicground shield assembly comprising an electrically conductive layer and afirst protective layer.

FIG. 3C depicts another sectional view of one embodiment of a ceramicground shield assembly comprising an electrically conductive layer and afirst protective layer.

FIG. 3D depicts another sectional view of one embodiment of a ceramicground shield assembly comprising an electrically conductive layer and afirst protective layer.

FIG. 4A depicts a sectional view of one embodiment of a ceramic groundshield assembly comprising an electrically conductive layer, a firstprotective layer, and a second protective layer.

FIG. 4B depicts another sectional view of one embodiment of a ceramicground shield assembly comprising an electrically conductive layer, afirst protective layer, and a second protective layer.

FIG. 4C depicts another sectional view of one embodiment of a ceramicground shield assembly comprising an electrically conductive layer, afirst protective layer, and a second protective layer.

FIG. 4D depicts another sectional view of one embodiment of a ceramicground shield assembly comprising an electrically conductive layer, afirst protective layer, and a second protective layer.

FIG. 5A depicts a sectional view of one embodiment of an electricallyconductive ground shield assembly comprising a first protective layerand a second protective layer.

FIG. 5B depicts another sectional view of one embodiment of anelectrically conductive ground shield assembly comprising a firstprotective layer and a second protective layer

FIG. 5C depicts another sectional view of one embodiment of anelectrically conductive ground shield assembly comprising a firstprotective layer and a second protective layer.

FIG. 5D depicts another sectional view of one embodiment of anelectrically conductive ground shield assembly comprising a firstprotective layer and a second protective layer.

FIG. 5E depicts another sectional side view of one embodiment of anelectrically conductive ground shield assembly comprising a firstprotective layer and a second protective layer.

FIG. 6 depicts a sectional view of one embodiment of a ground shieldassembly comprising a plurality of holes drilled through the plate ofthe ground shield wherein the plurality of holes is filled with anelectrically conductive plug.

FIG. 7 illustrates a first method for forming a ground shield assemblyas described herein.

FIG. 8 illustrates a second method of forming a ground shield assemblyas described herein.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure provide a ground shield as well asa substrate support assembly having a ground shield and a heatersurrounded by the ground shield. The ground shield includes a plate anda raised edge extending from the upper surface of the plate, where theraised edge includes an edge interior wall, an upper edge surface, andan edge exterior wall. The ground shield also includes a hollow shaftextending from the lower surface of the plate. The hollow surfaceincludes an interior wall and an exterior wall.

In one embodiment, the ground shield may be composed of a ceramicmaterial and an electrically conductive layer may be deposited onto atleast the upper surface of the plate. A first protective layer may bedeposited on the electrically conductive layer. A second layer may bedeposited on the first protective layer. By depositing the electricallyconductive layer on the ceramic ground shield body, the ground shield isable to provide a grounding function to the heater. The first protectivelayer and/or the second protective layer may protect the ground shieldfrom a high oxidation and/or a corrosive environment. For example, thefirst protective layer and/or second protective layer may be resistantto oxidation as well as erosion and/or corrosion from plasma and/or acorrosive chemistry (e.g., fluorine-rich environment and/orchlorine-rich environment). The first protective layer may bestrategically chosen such that the CTE value for the first protectivelayer and the CTE value for the ceramic material are substantiallysimilar, or within a suitable difference (e.g., within 2.5 10⁻⁶/° C.),so to prevent cracking of the first protective layer during substrateprocessing. By strategically choosing the ceramic material and the firstprotective layer to avoid CTE mismatch, the ground shield of the presentdisclosure may be used in biased, high temperature applications.

In another embodiment, the ground shield may be composed of anelectrically conductive material. A first protective layer may bedeposited on at least the upper surface of the plate of the groundshield. A second protective layer may be deposited on the firstprotective layer. The ground shield may be able to provide a groundingfunction to the heater without being damaged by a high oxidation orcorrosive processing environment. The first protective layer and thesecond protective layer may protect the ground shield from the highoxidation or corrosive environment. The electrically conductive materialand the first protective layer may be strategically chosen such that CTEvalue for the electrically conductive material and the CTE value for thefirst protective layer are substantially similar, or within a suitabledifference, (2.5 10⁻⁶/° C.), so to avoid cracking of the firstprotective layer during substrate processing. By strategically choosingthe electrically conductive material and the first protective layer toavoid CTE mismatch, the ground shield of the present disclosure may beused in biased, high temperature applications.

FIG. 1 illustrates a sectional view of a processing chamber 100 (e.g., asemiconductor processing chamber) having one or more chamber components.Processing chamber 100 may be used, for example, for semiconductormanufacturing processes, display manufacturing processes,micro-electrical mechanical system (MEMS) manufacturing processes,photovoltaic manufacturing processes, and so on. For example, processingchamber 100 may be a chamber for a plasma etcher or a plasma etchreactor, a plasma cleaner, a chemical vapor deposition (CVD) reactor, aphysical vapor deposition (PVD) reactor, an atomic layer deposition(ALD) reactor, and so forth.

In one embodiment, processing chamber 100 may include a chamber body 102that encloses an interior volume 106. Chamber body 102 may be fabricatedfrom aluminum, stainless steel or other suitable material. Chamber body102 generally includes a lid 104, sidewalls 108, and a bottom 110. Anouter liner 116 may be disposed adjacent the sidewalls 108 to protectchamber body 102. In one embodiment, outer liner 116 may be fabricatedfrom aluminum oxide.

An exhaust port 126 may be defined in chamber body 102, and may couplethe interior volume 106 to a pump system 128. Pump system 128 mayinclude one or more pumps and throttle valves utilized to evacuate andregulate the pressure of interior volume 106 of processing chamber 100.

A gas panel 158 may be coupled to processing chamber 100 to provideprocess and/or cleaning gases to interior volume 106 through one or moreintermediate components.

Examples of processing gases that may be used to process substrates inthe processing chamber 100 include halogen-containing gases, such asC₂F₆, SF₆, SiCl₄, HBr, NF₃, CF₄, CHF₃, CH₂F₃, F, NF, Cl₂, CCl₄, BCl₄,and SiF₄, among others, and other gases such as O₂, NH₃, H₂, or N₂O.Examples of carrier gases include N₂, He, Ar, and other gases inert toprocess gases (e.g., non-reactive gases).

Processing chamber 100 may include multiple showerheads, faceplatesand/or gas distribution plates, which may be arranged in series. Ashowerhead 160 may be defined in chamber body 102 and may be coupled toand/or proximate to lid 104. Alternatively, lid 104 may be replaced byshowerhead 160. Showerhead 160 may be positioned within processingchamber 100 as illustrated, and may be included or positioned betweenlid 104 and a substrate support assembly 148. In embodiments, showerhead160 may be or include a metallic or conductive component that is acoated, seasoned or otherwise treated material. Exemplary materials mayinclude metals, including aluminum, as well as metal oxides, includingaluminum oxide. Depending on the precursors being utilized, or theprocess being performed within processing chamber 100, the showerhead160 may be any other metal that may provide structural stability as wellas electrical conductivity.

Showerhead 160 may define one or more apertures to facilitate uniformdistribution of precursors and/or plasma through showerhead 160. Theapertures may be included in a variety of configurations and patterns,and may be characterized by any number of geometries that may provideprecursor and/or plasma distribution as may be desired. Showerhead 160may be electrically coupled with a power source in embodiments. Forexample, showerhead 160 may be coupled with an RF source 170. Whenoperated, RF source 170 may provide a current to showerhead 160 allowinginductively-coupled plasma (ICP) or conductively coupled plasma (CCP) tobe formed between showerhead 160 and another component.

Chamber body 102 may also include a face plate 162. Faceplate 162 may besimilar to the showerhead 160. Faceplate 162 may be positioned withinprocessing chamber 100 between showerhead 160 and substrate supportassembly 148. Faceplate 162 may include a plurality of channels orapertures defined through faceplate 162. Faceplate 162 may be or includean insulative material. In one embodiment, faceplate 162 may be quartzor any material that may have reduced interaction with oxygen-containingplasma effluents, such as a reduced impact on oxygen, or oxygen radical,recombination as compared to metal oxide components.

A second showerhead 164 may be defined in chamber body 102 and mayoperate as an additional electrode with showerhead 160. Showerhead 164may include any of the features or characteristics of showerhead 160discussed previously. In other embodiments, certain features ofshowerhead 164 may diverge from the showerhead 160. For example,showerhead 164 may be coupled with an electrical ground 172, which mayallow ICP or CCP to be generated between showerhead 160 and showerhead164. In one embodiment, ICP or CCP may be generated between showerhead160 and faceplate 162. Showerhead 164 may define apertures within thestructure to allow precursors or plasma effluents to be delivered to asubstrate 144 during processing.

A gas distribution assembly 166 may optionally be defined in chamberbody 102. In some embodiments, there may be no components betweenshowerhead 164 and substrate support assembly 148, and showerhead 164may allow distribution of precursors and/or plasma effluents to asubstrate 144 during processing. Gas distribution assembly 166 may belocated within the chamber body 102 above substrate support assembly 148and lid 104, as well as between substrate support assembly 148 andshowerhead 164. Gas distribution assembly 166 may be configured todeliver both a first and second precursor to substrate support assembly148.

In one embodiment, gas distribution assembly 166 may be configured tohave two or more gas feeding channels, to allow a precursor and/orplasma delivered by a showerhead 164 to pass through gas distributionassembly 166 and access substrate support assembly 148. In anotherembodiment, gas distribution assembly 166 may allow a precursor and/orplasma from another source, (e.g., a remote plasma source (not shown))to pass through gas distribution assembly 166 and access substratesupport assembly 148.

A second faceplate 168 may be defined in chamber body 102. In someembodiments, faceplate 168 may provide similar functionality, andinclude similar characteristics, as faceplate 162, or showerheads 160,164. Substrate support assembly 148 may be coupled with an RF source176. In particular, the ground shield 149 of substrate support assembly148 may be coupled with RF source 176. Faceplate 168 may be coupled withan electrical ground 174. When operated, RF source 176 may provide acurrent to substrate support assembly 148 allowing biased plasma to beformed between faceplate 168 and substrate 144. Faceplate 168 may becoupled with an electrical ground 174 in embodiments.

Substrate support assembly 148 may be disposed in interior volume 106 ofprocessing chamber 100 below a showerhead and/or gas diffuser 160.Substrate support assembly 148 may hold a substrate 144 duringprocessing. In one embodiment, the substrate support assembly 148 mayinclude a ground shield 149 and a heater 150. Heater 150 may includeheater body that includes a plate 154A (or disc) and a shaft 154B (e.g.,a cylindrical shaft) that extends from a lower surface of the disc orplate. Ground shield 149 may include a ground shield body that includesa plate or disc and a shaft that extends from a lower surface of theplate or disc. The shaft of the ground shield 149 may be a hollow shaft,and the shaft 154B of the heater 150 may be disposed inside of thehollow shaft of the ground shield 149. The ground shield body mayadditionally include a raised edge extending from an upper surface ofthe plate or disc (e.g., a ring at a periphery of the plate). The plate154A of heater 150 may rest inside of the raised edge of ground shield149, and raised edge of the ground shield 149 may protect side walls ofheater 150.

In one embodiment, heater 150 is composed of AlN (aluminum nitride).Alternatively, heater 150 may be composed of SiC (silicon carbide), orother materials. In one embodiment, heater 150 may include one or moreresistive heating elements 155 disposed in the heater body. In oneembodiment, the one or more resistive heating elements 155 may bedisposed in the plate 154A.

Heater 150 may heat substrate 144 to working temperatures of 450° C.,500° C., or higher during processing. Traditional ground shields arecomposed of aluminum or stainless steel, and include a coating of plasmasprayed Y₂O₃ (yttria or yttrium oxide). However, the aluminum orstainless steel of the traditional ground shields have much higher CTEvalues than the CTE of Y₂O₃. For example, aluminum has a CTE of about21-24×10⁻⁶/° C., stainless steel has a CTE of between about 7.6 and17.3×10⁻⁶PC, and Y₂O₃ has a CTE of 7.2×10⁻⁶/° C. This mismatch in CTEvalues causes the Y₂O₃ coating to crack and delaminate from the body ofthe traditional ground shield at working temperatures of 450° C. orabove.

Accordingly, in some embodiments at least the plate of ground shield 149is composed of a bulk ceramic material. The shaft of ground shield 149may be the same ceramic material or may be a different material than thematerial used for the plate. Examples ceramic materials that may be usedfor the plate of the ground shield (and optionally the shaft of theground shield) may include Al₂O₃ (alumina), AlN, Si (silicon), SiC, SiN(silicon nitride), Y₃Al₅O₁₂ (YAG), Y₄Al₂O₉(YAM), Y₅O₄F₇, Y₂O₃, Er₂O₃,Gd₂O₃, Gd₃Al₅O₁₂ (GAG), YF₃, YAlO₃ (YAP), Nd₂O₃, Er₄Al₂O₉(EAM),Er₃Al₅O₁₂ (EAG), ErAlO₃ (EAP), Gd₄Al₂O₉(GAM), GdAlO₃ (GAP), Nd₃Al₅O₁₂,Nd₄Al₂O₉, NdAlO₃, or a ceramic compound composed of Y₄Al₂O₉ and a solidsolution of Y₂O₃—ZrO₂.

In order to provide RF grounding (and thus function as a ground shield),ground shield 149 should include an electrically conductive component.Accordingly, ground shield 149 may include an electrically conductivelayer 151 on at least an upper surface of the plate of ground shield150. Electrically conductive layer 151 may be composed of Mo(Molybdenum), W (Tungsten), Ta (Tantalum), Ni (Nickel), Hastelloy® (analloy of nickel, molybdenum, and chromium), Inconel® (an alloy ofnickel, chromium, and iron), Ti (titanium), a Ti alloy (e.g., TC4), ITO(indium tin oxide), etc. As used herein, the term electricallyconductive layer means a layer having an electrical resistivity of 5 Ωcmor less at a temperature between about 20° C. to about 800° C.Electrically conductive layer 151 may be a solid layer or may be apatterned or printed layer (e.g., having one or more patterns, such as aweb-like pattern, a grid pattern, a bullseye pattern, a spiral pattern,and so on). Electrically conductive layer 151 may be connected to ground190 at one or multiple points, as described further below. Since groundshield 149 provides RF grounding, it may have multiple paths to ground(e.g., 190A, 190B) to minimize parasitic capacitance and/or inductanceand to present an equivalent low impedance at frequencies of interest atvarious points on ground shield 149.

Electrically conductive layer 151 is coated with a first protectivelayer 152. First protective layer 152 may be thicker than electricallyconductive layer 151 and may be composed of a material that has a CTEthat is close to the CTE of the body of ground shield 149. Firstprotective layer 152 may be composed of conductive or non-conductivemetals, alloys, ceramics, and other composited materials. Firstprotective layer 152 may have good oxidation resistance and may beplasma resistant at temperatures of 450° C. or above. In embodiments,first protective layer 152 may be composed of Al₂O₃, Y₂SiO₅, Y₂Si₂O₇,Ta, a titanium alloy (e.g., TC4), SiC, Y₂O₃, Y₄Al₂O₉, Y₃Al₅O₁₂, YAlO₃,Y₅O₄F₇, Quartz, Si₃N₄, AlN, AlON (aluminum oxynitride), TiO₂ (titania),ZrO₂ (zirconia), TiC (titanium carbide), ZrC (zirconium carbide), TiN(titanium nitride), TiCN (titanium carbon nitride), Y₂O₃ stabilized ZrO₂(YSZ).

First protective layer 152 may be coated with a second protective layer153. Second protective layer 153 may be a thin layer that seals anycracks and/or pores in first protective layer 152. Second protectivelayer 153 may be composed of Y₂SiO₅, Y₂Si₂O₇, Ta, a titanium alloy(e.g., TC, TC4), SiC, Y₄Al₂O₉, Y₃Al₅O₁₂, YAlO₃, Y₅O₄F₇, Quartz, Si₃N₄,AlN, AlON, TiO₂, ZrO₂, TiC, ZrC, TiN, TiCN, Y₂O₃ stabilized ZrO₂ (YSZ),and so on. Second protective layer 153 may also be composed of a ceramiccomposite such as Y₃Al₅O₁₂ distributed in Al₂O₃ matrix, Y₂O₃—ZrO₂ solidsolution or a SiC—Si₃N₄ solid solution.

Other example compositions for first protective layer 152 and/or secondprotective layer 153 include Y₂O₃, Al₂O₃, Er₂O₃, YF₃, Er₃Al₅O₁₂, Y—O—F(e.g., Y₅O₄F₇), Er₃Al₅O₁₂, Er₄Al₂O₉, ErAlO₃, a solid solution ofY₂O₃—ZrO₂, and a ceramic compound comprising Y₄Al₂O₉ and asolid-solution of Y₂O₃—ZrO₂.

With reference to the solid-solution of Y₂O₃—ZrO₂, first protectivelayer 152 and/or second protective layer 153 may include Y₂O₃ at aconcentration of 10-90 molar ratio (mol %) and ZrO₂ at a concentrationof 10-90 mol %. In some examples, the solid-solution of Y₂O₃—ZrO₂ mayinclude 10-20 mol % Y₂O₃ and 80-90 mol % ZrO₂, may include 20-30 mol %Y₂O₃ and 70-80 mol % ZrO₂, may include 30-40 mol % Y₂O₃ and 60-70 mol %ZrO₂, may include 40-50 mol % Y₂O₃ and 50-60 mol % ZrO₂, may include60-70 mol % Y₂O₃ and 30-40 mol % ZrO₂, may include 70-80 mol % Y₂O₃ and20-30 mol % ZrO₂, may include 80-90 mol % Y₂O₃ and 10-20 mol % ZrO₂, andso on.

With reference to the ceramic compound comprising Y₄Al₂O₉ and asolid-solution of Y₂O₃—ZrO₂, in one embodiment the ceramic compoundincludes 62.93 mol % Y₂O₃, 23.23 mol % ZrO₂ and 13.94 mol % Al₂O₃. Inanother embodiment, the ceramic compound can include Y₂O₃ in a range of50-75 mol %, ZrO₂ in a range of 10-30 mol % and Al₂O₃ in a range of10-30 mol %. In another embodiment, the ceramic compound can includeY₂O₃ in a range of 40-100 mol %, ZrO₂ in a range of 0.1-60 mol % andAl₂O₃ in a range of 0.1-10 mol %. In another embodiment, the ceramiccompound can include Y₂O₃ in a range of 40-60 mol %, ZrO₂ in a range of30-50 mol % and Al₂O₃ in a range of 10-20 mol %. In another embodiment,the ceramic compound can include Y₂O₃ in a range of 40-50 mol %, ZrO₂ ina range of 20-40 mol % and Al₂O₃ in a range of 20-40 mol %. In anotherembodiment, the ceramic compound can include Y₂O₃ in a range of 60-80mol %, ZrO₂ in a range of 0.1-10 mol % and Al₂O₃ in a range of 20-40 mol%. In another embodiment, the ceramic compound can include Y₂O₃ in arange of 40-60 mol %, ZrO₂ in a range of 0.1-20 mol % and Al₂O₃ in arange of 30-40 mol %. In other embodiments, other distributions may alsobe used for the ceramic compound.

In one embodiment, an alternative ceramic compound that includes acombination of Y₂O₃, ZrO₂, Er₂O₃, Gd₂O₃ and SiO₂ is used for the groundshield body of ground shield 149. In one embodiment, the alternativeceramic compound can include Y₂O₃ in a range of 40-45 mol %, ZrO₂ in arange of 0-10 mol %, Er₂O₃ in a range of 35-40 mol %, Gd₂O₃ in a rangeof 5-10 mol % and SiO2 in a range of 5-15 mol %. In another embodiment,the alternative ceramic compound can include Y₂O₃ in a range of 30-60mol %, ZrO₂ in a range of 0-20 mol %, Er₂O₃ in a range of 20-50 mol %,Gd₂O₃ in a range of 0-10 mol % and SiO2 in a range of 0-30 mol %. In afirst example, the alternative ceramic compound includes 40 mol % Y₂O₃,5 mol % ZrO₂, 35 mol % Er₂O₃, 5 mol % Gd₂O₃ and 15 mol % SiO₂. In asecond example, the alternative ceramic compound includes 45 mol % Y₂O₃,5 mol % ZrO₂, 35 mol % Er₂O₃, 10 mol % Gd₂O₃ and 5 mol % SiO₂. In athird example, the alternative ceramic compound includes 40 mol % Y₂O₃,5 mol % ZrO₂, 40 mol % Er₂O₃, 7 mol % Gd₂O₃ and 8 mol % SiO₂. In oneembodiment, the ground shield body may be composed of a material thatincludes 70-75 mol % Y₂O₃ and 25-30 mol % ZrO₂. In a further embodiment,the ground shield 200 body is composed of a material entitled YZ-20 thatincludes 73.13 mol % Y₂O₃ and 26.87 mol % ZrO₂.

Any of the aforementioned porous coatings may include trace amounts ofother materials such as ZrO₂, Al₂O₃, SiO₂, B₂O₃, Er₂O₃, Nd₂O₃, Nb₂O₅,CeO₂, Sm₂O₃, Yb₂O₃, or other oxides.

FIG. 2 depicts an exploded view of one embodiment of a ground shield200. Ground shield 200 may correspond with ground shield 149 depicted inFIG. 1 . Ground shield may include a plate 204 and a raised edge 206extending from the upper surface of plate 204. In one embodiment, groundshield 200 further includes a hollow shaft 214 that extends from a lowersurface of plate 204. Hollow shaft 214 includes an interior wall 216 andan exterior wall 218.

In one embodiment, plate 204 may have a shape that correspondsapproximately to a shape of a heater that is to be protected. Forexample, a top of the heater may be circular, and plate 204 may have adisc shape, as shown. Plate 204 may have a thickness of between about0.20 inches to about 2.00 inches.

In one embodiment, plate 204 may have a plurality of holes drilledthrough plate 204. The plurality of holes may be filled with anelectrically conductive plug. The electrically conductive plug mayprovide a path to ground for an electrically conductive layer on theupper surface of the plate 204. Electrically conductive plugs (e.g.,vias) are discussed in greater detail below with reference to FIG. 6 .

Raised edge 206 may extend from the upper surface of plate 204 and mayinclude an edge interior wall 208, an edge upper surface 210, and anedge exterior wall 212. Edge interior wall 208 may have a height ofbetween about 0.20 inches to about 2.00 inches. Edge upper surface 210may have a width of between about 0.05 inches to about 0.50 inches. Edgeexterior wall 212 may have a height of between about 0.20 inches toabout 4.00 inches. In one embodiment, raised edge 206 may have a shapethat corresponds approximately to the shape of the heater that is to begrounded. For example, edge interior wall 208 may have a height thatcorresponds to the height of the circular disk of the heater that willbe encircled by raised edge 206.

In another embodiment, ground shield 200 may further include hollowshaft 214 that extends from the lower surface of plate 204. Hollow shaft214 may include interior wall 216 and exterior wall 218. In oneembodiment, hollow shaft 214 may have a shape that corresponds to theshape of the heater that is to be grounded. For example, interior wall216 may have a diameter that corresponds, or is slightly larger than,the diameter of the cylindrical shaft 154B of the heater 150.

In one embodiment, plate 204 and hollow shaft 214 of ground shield 200may be a single component (e.g., a single sintered ceramic body).Alternatively, plate 204 may be a separate component than hollow shaft214. In such an embodiment, the plate 204 may be coupled to hollow shaft214, such as with bolts or other fasteners. In one embodiment, hollowshaft 214 may be composed of two sections, which may be identical ornear-identical sections. These sections may come together (e.g., bebolted together) about the shaft 154B of a heater 150. The combinedsections of hollow shaft 214 may then be secured to plate 204.

In one embodiment, ground shield 200 may include a bulk sintered ceramicmaterial. Ground shield 200 may have a composition of one or more ofAl₂O₃, AlN, Si, SiC, SiN, ZrO₂, Y₃Al₅O₁₂, Y₄Al₂O₉, Y₅O₄F₇, Y₂O₃, Er₂O₃,Gd₂O₃, Gd₃Al₅O₁₂, YF₃, Nd₂O₃, Er₄Al₂O₉, Er₃Al₅O₁₂ (EAG), ErAlO₃,Gd₄Al₂O₉, GdAlO₃, Nd₃Al₅O₁₂, Nd₄Al₂O₉, or NdAlO₃.

In one embodiment, plate 204 and raised edge 206 may not have the samecomposition as hollow shaft 214. For example, plate 204 and raised edge206 may be composed of any of the aforementioned bulk sintered ceramicmaterials, while hollow shaft 214 may be composed of a stronger,metallic material, such as stainless steel or aluminum.

In one embodiment, ground shield 200 is composed of a bulk sinteredceramic material and further includes an electrically conductive layer220 deposited on at least the upper surface of plate 204 and a firstprotective layer 222 deposited on at least electrically conductive layer220.

Electrically conductive layer 220 may have a composition of one or moreof Mo, W, Ta, Ti, TC4, Hastelloy®, Inconel®, ITO, or anotherelectrically conductive material that is stable in a high temperatureenvironment. In one embodiment, electrically conductive layer 220 has acomposition of a material that provides good oxidation resistance atprocessing temperatures, such as temperatures of 450° C. or above (e.g.,Hastelloy®). Electrically conductive layer 220 may be deposited bytraditional atmospheric plasma spray, low pressure plasma spray (LPPS),vacuum plasma spray (VPS), screen printing, wet chemical deposition(e.g., sol gel), physical vapor deposition (PVD), chemical vapordeposition (CVD), aerosol deposition, evaporation, atomic layerdeposition (ALD), plasma enhanced chemical vapor deposition (PEVCVD),ion assisted deposition (IAD), ion plating, immersion coating,sputtering, thermal spraying, hot isostatic pressing, cold isostaticpressing, lamination, compression molding, casting, compacting,sintering or co-sintering techniques. Electrically conductive layer 220may have a thickness of between about 0.05 μm and 2.00 mm.

First protective layer 222 may be composed of a plasma resistant ceramicmaterial. First protective layer may have a composition of Al₂O₃,Y₂SiO₅, Y₂Si₂O₇, Ta, Ta₂O₅, a titanium alloy (e.g., TC4), SiC, Y₂O₃,Y₄Al₂O₉, Y₃Al₅O₁₂, YAlO₃, Y₅O₄F₇, Quartz, Si₃N₄, AlN, AlON, TiO₂, ZrO₂,TiC, ZrC, TiN, TiCN, Y₂O₃ stabilized ZrO₂, and so on. First protectivelayer 222 may also be composed of a ceramic composite such as Y₃Al₅O₁₂distributed in Al₂O₃ matrix, Y₂O₃—ZrO₂ solid solution or a SiC—Si₃N₄solid solution. First protective layer 222 may also be a ceramiccomposite that includes a yttrium oxide (also known as yttria and Y₂O₃)containing solid solution. For example, first protective layer 222 maybe composed of a ceramic composite that is composed of a compoundY₄Al₂O₉ and a solid solution Y₂-xZr_(x)O₃(Y₂O₃—ZrO₂ solid solution).Note that pure yttrium oxide as well as yttrium oxide containing solidsolutions may be doped with one or more of ZrO₂, Al₂O₃, SiO₂, B₂O₃,Er₂O₃, Nd₂O₃, Nb₂O₅, CeO₂, Sm₂O₃, Yb₂O₃, or other oxides.

In one embodiment, first protective layer 222 may be composed of acomposite ceramic coating including a compound Y₄Al₂O₉ and a solidsolution Y₂-xZr_(x)O₃(Y₂O₃—ZrO₂ solid solution). In a furtherembodiment, the composition of first protective layer 222 may include62.93 mol % Y₂O₃, 23.23 mol % ZrO₂ and 13.94 mol % Al₂O₃. In anotherembodiment, the composite ceramic coating may include Y₂O₃ in a range of50-75 mol %, ZrO₂ in a range of 10-30 mol % and Al₂O₃ in a range of10-30 mol %. In other embodiments, other distributions may also be usedfor the composite ceramic coating. In one embodiment, the compositeceramic is a yttrium oxide containing solid solution that may be mixedwith one or more of ZrO₂, Al₂O₃, or combination thereof.

In one embodiment, first protective layer 222 may be composed of yttriumaluminum garnet (YAG) composed of 35 mol % Y₂O₃, 65 mol % Al₂O₃. Inanother embodiment, first protective layer 222 may be composed of YAGcomposed of 30-40 mol % Y₂O₃ and 60-70 mol % Al₂O₃.

First protective layer 222 may also be composed of other materialsdiscussed herein above.

First protective layer 222 may be deposited by traditional atmosphericplasma spray, LPPS, VPS, screen printing, wet chemical deposition (e.g.,sol gel), PVD, CVD, aerosol deposition, evaporation, PECVD, IAD, Ionplating, immersion coating, sputtering, thermal spraying, hot isostaticpressing, cold isostatic pressing, lamination, compression molding,casting, compacting, sintering or co-sintering techniques. In oneembodiment, the first protective layer 222 may have a thickness ofbetween about 50.00 nm and about 2.00 mm. In another embodiment, firstprotective layer 222 may have a thickness of between about 1.00 μm andabout 2.00 mm. In one embodiment, first protective layer 222 may havecracks and a porosity of about 0.10-10.0% (e.g., about 0.10-1%, 1-5%,1-3%, 3-5%, 5-7%, and so on).

In one embodiment, first protective layer 222 may be composed of Al₂O₃and may be deposited by either traditional atmospheric plasma spray,LPPS, or VPS. In a further embodiment, first protective layer 222 mayhave a porosity of approximately zero (e.g., a porosity of less than0.1%).

In one embodiment, first protective layer 222 is polished to a certainsmoothness. First protective layer 222 may be polished by a grinder orchemical mechanical planarization (CMP) machine. A grinder is a machinehaving an abrasive disk that grinds and/or polishes a surface of anarticle. The grinder or CMP machine may grind a surface of firstprotective layer 222 to decrease the roughness of the layer and/or toreduce the thickness of the layer. In one embodiment, first protectivelayer 222 may be polished to have an average roughness of less than 0.10microns or less.

In one embodiment, the material used for first protective layer 222 maybe suitably chosen so that a CTE for first protective layer 222 matchesthe CTE of ceramic ground shield 200 in order to minimize the CTEmismatch between ceramic ground shield 200 and first protective layer222 and avoid thermo-mechanical stresses which may damage firstprotective layer 222 during processing. In one embodiment, the CTE forfirst protective layer 222 has a value difference within approximately2.5×10⁻⁶/° C. of the CTE for ceramic ground shield 200 (e.g., for theplate of the ceramic ground shield 200). In one embodiment, ceramicground shield 200 may be composed of Al₂O₃ and first protective layer222 may be composed of a material that has a CTE difference withinapproximately 2.5×10⁻⁶/° C. of the CTE for ceramic ground shield 200.

In a further embodiment, ground shield 200 may be composed of a bulksintered ceramic material further includes an electrically conductivelayer 220 deposited on at least upper surface of the plate 204, a firstprotective layer 222 deposited on at least the electrically conductivelayer 220, and a second protective layer 224 deposited on at least firstprotective layer 222.

Electrically conductive layer 220 may be composed of any electricallyconductive material disclosed herein. First protective layer 222 may becomposed of any ceramic material disclosed herein.

Second protective layer 224 may be composed of Y₂O₃, Er₂O₃, Ta₂O₅, YF₃,Al₂O₃, AlF₃, ZrO₂, and their combinations. Second protective layer 224may also be composed of Y₂SiO₅, Y₂Si₂O₇, Ta, a titanium alloy (e.g.,TC4), SiC, Y₄Al₂O₉, Y₃Al₅O₁₂, YAlO₃, Y₅O₄F₇, Quartz, Si₃N₄, AlN, AlON,TiO₂, ZrO₂, TiC, ZrC, TiN, TiCN, Y₂O₃ stabilized ZrO₂, and so on. Secondprotective layer 224 may also be a ceramic composite such as Y₃Al₅O₁₂distributed in Al₂O₃ matrix, a Y₂O₃—ZrO₂ solid solution or a SiC—Si₃N₄solid solution. Second protective layer 224 may also be a ceramiccomposite that includes a yttrium oxide (also known as yttria and Y₂O₃)containing solid solution. For example, second protective layer 224 maybe a ceramic composite that is composed of a compound Y₄Al₂O₉ and asolid solution Y₂-xZr_(x)O₃(Y₂O₃—ZrO₂ solid solution). Note that pureyttrium oxide as well as yttrium oxide containing solid solutions may bedoped with one or more of ZrO₂, Al₂O₃, SiO₂, B₂O₃, Er₂O₃, Nd₂O₃, Nb₂O₅,CeO₂, Sm₂O₃, Yb₂O₃, or other oxides.

In one embodiment, second protective layer 224 is a composite ceramiccoating composed of a compound Y₄Al₂O₉ and a solid solutionY₂-xZr_(x)O₃(Y₂O₃—ZrO₂ solid solution). In a further embodiment, thecomposition of second protective layer 224 may include 62.93 mol % Y₂O₃,23.23 mol % ZrO₂ and 13.94 mol % Al₂O₃. In another embodiment, secondprotective layer 224 may include Y₂O₃ in a range of 50-75 mol %, ZrO₂ ina range of 10-30 mol % and Al₂O₃ in a range of 10-30 mol %. In otherembodiments, other distributions may also be used for the compositeceramic coating. In one embodiment, the composite ceramic is a yttriumoxide containing solid solution that may be mixed with one or more ofZrO₂, Al₂O₃, or combination thereof.

In one embodiment, second protective layer 224 may be composed of YAGcomposed of 35 mol % Y₂O₃, 65 mol % Al₂O₃. In another embodiment, secondprotective layer 224 can be YAG composed of 30-40 mol % Y₂O₃ and 60-70mol % Al₂O₃. Second protective layer 224 may have a porosity between 0.1and 10.0%.

Second protective layer 224 may also be composed of any of the othermaterials disclosed herein above with reference to first protectivelayer 224.

Second protective layer 224 may be deposited by traditional atmosphericplasma spray, LPPS, VPS, screen printing, wet chemical deposition (e.g.,sol gel), PVD, CVD, aerosol deposition, evaporation, PEVCVD, IAD, ionplating, immersion coating, sputtering, thermal spraying, hot isostaticpressing, cold isostatic pressing, lamination, compression molding,casting, compacting, sintering or co-sintering techniques. In oneembodiment, second protective layer 224 may be deposited by ALD.

In one embodiment, second protective layer 224 may have a thickness ofbetween about 50.00 nm and about 2.00 mm or thicker. In anotherembodiment, second protective layer 224 may have a thickness of betweenabout 1.00 μm and about 2.00 mm. Second protective layer 224 may be aconformal layer and may have a porosity of approximately zero (e.g., aporosity of less than 0.1%). In one embodiment, first protective layer222 may have cracks and a porosity of about 0.10-10.0% (e.g., about0.10-1%, 1-5%, 1-3%, 3-5%, 5-7%, and so on). Second protective layer 224may be a top coat layer that seals the pores and/or cracks in the firstprotective layer 222. Because second protective layer 224 is very thin,the CTE of second protective layer 224 may not match the CTE of firstprotective layer 222 or plate 204.

In some embodiments, second protective layer 224 is deposited beforefirst protective layer 222. In such embodiments, second protective layer224 may protect electrically conductive layer 220 from gases and/orplasmas that penetrate cracks and/or pores in first protective layer222.

Electrically conductive layer 220, first protective layer 222 and secondprotective layer 224 are shown as covering the upper surface of theplate 204, in accordance with one embodiment. In alternativeembodiments, one or more of electrically conductive layer 220, firstprotective layer 222 and/or second protective layer 224 may additionallycover the edge interior wall 208, the edge upper surface 210, the edgeexterior wall 212, the shaft interior 216, the shaft exterior 218, thelower surface of the plate 204 and/or other surfaces of the groundshield 200. In these embodiments, the electrically conductive layer 220may provide alternate paths to ground to facilitate the function ofground shield 200. For example, electrically conductive layer 220 maycover shaft interior wall 216 or shaft exterior 218. Some embodimentsare shown below with reference to FIGS. 3A-5E.

In one embodiment, the material for first protective layer 222 may besuitably chosen for its resistance to a chlorine gas processingenvironment. For example, first protective layer 222 may be composed ofa titanium alloy (e.g., TC4), Hastelloy®, or any other chlorineresistant materials with target CTE values. In one embodiment, thematerial for second protective layer 224 may also be suitably chosen forits resistance to a chlorine gas processing environment and may becomposed of any of the chlorine resistant materials described above thathave target CTE values.

In one embodiment, the material for first protective layer 222 may besuitably chosen for its resistance to a fluorine gas processingenvironment. For example, first protective layer 222 may be composed ofYF₃, AlF₃, Er₂O₃, or any other fluorine resistant materials. In oneembodiment, the material for second protective layer 224 may also besuitably chosen for its resistance to a fluorine gas processingenvironment and may be composed of any of the fluorine resistantmaterials described above that have target CTE values.

In a further embodiment, ground shield 200 may further include a thirdprotective layer (not shown) that is deposited on second protectivelayer 224. The third protective layer may be composed of Y₂O₃, Er₂O₃,Ta₂O₅, YF₃, Al₂O₃, AlF₃, ZrO₂, and their combinations. In oneembodiment, the third protective layer may have cracks and a porosity ofabout 0.10-10.0% (e.g., about 0.10-1%, 1-5%, 1-3%, 3-5%, 5-7% and soon). In another embodiment, the third protective layer may be aconformal layer and may have a porosity of approximately zero (e.g., aporosity of less than 0.1%).

The third protective layer may be deposited by traditional atmosphericplasma spray, LPPS, VPS, screen printing, wet chemical deposition (e.g.,sol gel), PVD, CVD, ALD, aerosol deposition, evaporation, PECVD, IAD,ion plating, immersion coating, sputtering, thermal spraying, hotisostatic pressing, cold isostatic pressing, lamination, compressionmolding, casting, compacting, sintering or co-sintering techniques. Thethird protective layer may have a thickness of between about 50 nm to 5μm or thicker. The third protective layer may be a conformal layer.

In one embodiment, ground shield 200 may be composed of an electricallyconductive material and may further include a first protective layer 222deposited on at least the upper surface of plate 204 and a secondprotective coating 224 deposited on the first protective coating 222. Insuch embodiments, electrically conductive layer 220 may be omitted.

The electrically conductive material may have a composition of one ormore of Mo, W, Ta, Hastelloy®, Inconel®, ITO, Si, or SiC, or any othermaterial that is stable in a high temperature environment. In oneembodiment, an electrically conductive metal matrix composite (MMC)material is used for ground shield 200. The MMC material includes ametal matrix and a reinforcing material which is embedded and dispersedthroughout the matrix. The metal matrix may include a single metal ortwo or more metals or metal alloys. Metals which may be used include butare not limited to aluminum (Al), magnesium (Mg), titanium (Ti), cobalt(Co), cobalt-nickel alloy (CoNi), nickel (Ni), chromium (Cr), gold (Au),silver (Ag) or various combinations thereof. The reinforcing materialmay be selected to provide the desired structural strength for the MMC,and may also be selected to provide desired values for other propertiesof the MMC, such as thermal conductivity and CTE, for example. Examplesof reinforcing materials which may be used include Si, carbon (C), orSiC, but other materials may also be used.

First protective layer 222 and second protective layer 224 may becomposed of any of the appropriate materials discussed herein above.

In one embodiment, the material used for first protective layer 222 maybe suitably chosen so that a CTE for first protective layer 222 matchesthe CTE of electrically conductive ground shield 200 in order tominimize the CTE mismatch between electrically conductive ground shield200 and first protective layer 222 and avoid thermo-mechanical stresseswhich may damage first protective layer 222 during processing. Inanother embodiment, the material used for first protective layer 222 maybe suitable chosen so that a CTE for first protective layer 222substantially matches (e.g., is within 2.5×10⁻⁶/° C.) the CTE ofelectrically conductive ground shield 200. In one embodiment, the bodyof ground shield 200 may be composed of a material suitably chosen sothat a CTE for the body of ground shield 200 substantially matches theCTE of Al₂O₃ (or one of the other ceramic materials listed above for thefirst protective layer 222), and first protective layer 222 may becomposed of Al₂O₃ (or one of the other materials listed above for thefirst protective layer). For example, the body of ground shield 200 maybe composed of a titanium alloy (e.g., TC4), which has a CTE thatmatches the CTE of Al₂O₃, and first protective layer 222 is composed ofAl₂O₃. In another embodiment, the body of ground shield 200 may becomposed of a material suitably chosen so that a CTE for the body ofground shield 200 may be within 2.5×10⁻⁶/° C. of the CTE of Al₂O₃. Inanother embodiment, the body of ground shield 200 may be composed of SiCand first protective layer 222 is composed of Y₂SiC or Y₂Si₂O₇.

FIGS. 3A-3D illustrate cross sectional side views of various embodimentsfor a ceramic ground shield 200 including the structure shown in FIG. 2with electrically conductive layer 220 and first protective layer 222.FIG. 3A depicts one embodiment wherein electrically conductive layer 302may be deposited on the upper surface of the plate 204. First protectivelayer 304 may be deposited on electrically conductive layer 302. FIG. 3Bdepicts an alternative embodiment wherein electrically conductive layer302 may be further deposited on edge interior wall 208 and edge uppersurface 210. First protective layer 304 may be deposited on electricallyconductive layer 302. FIG. 3C depicts another alternative embodimentwherein electrically conductive layer 302 may be deposited on the uppersurface of the plate 204 and on the interior wall 216 of the hollowshaft 214. First protective layer 304 may be deposited on electricallyconductive layer 302. FIG. 3D depicts another alternative embodimentwherein electrically conductive layer 302 may be deposited on the uppersurface of plate 204, edge interior wall 208, edge upper surface 210,edge exterior wall 212, the lower surface of plate 204 and exterior wall218 of hollow shaft 214.

In further embodiments, electrically conductive layer 302 and firstprotective layer 304 may completely cover each surface of the groundshield 200 or may cover edge exterior wall 212 and/or the lower surfaceof plate 204 in addition to any of the surfaces of ground shield 200that these layers are shown to cover in the illustrated examples. Infurther embodiments, electrically conductive layer 302 may cover anysurfaces of ground shield 200 shown, but first protective layer 304 maycompletely cover each surface of ground shield 200 or alternatively maycover edge exterior wall 212 and/or the lower surface of plate 204 inaddition to any of the surfaces of ground shield 200 that firstprotective layer 304 is shown to cover in the illustrated examples.

In any of the embodiments depicted in FIGS. 3A-3D, the first protectivelayer 304 may completely cover electrically conductive layer 302 so thatelectrically conductive layer 302 may not be exposed to the processingenvironment of the processing chamber depicted in FIG. 1 . This allowselectrically conductive layer 302 to avoid corrosion in the presence ofa high oxidation and/or corrosive environment. Additionally, in any ofthe embodiments depicted in FIGS. 3A-3D, first protective layer 304 maybe deposited on any surface of the ground shield 200 that is not coveredby electrically conductive layer 302. For example, electricallyconductive layer 302 may be deposited on upper surface of the plate 204and first protective layer 304 may be deposited on electricallyconductive layer 302 and edge interior wall 208.

In another embodiment not shown, ground shield 200 may be composed of aceramic material. An electrically conductive layer 302 may be depositedonto the upper surface of plate 204, edge interior wall 208, edge uppersurface 210, and edge exterior wall 212. A first protective coating 304may be deposited on electrically conductive layer 302. In a furtherembodiment, electrically conductive layer 302 may be also deposited onthe lower surface of plate 204. First protective layer 304 may bedeposited onto electrically conductive layer 302.

FIGS. 4A-4D illustrate cross sectional side views of various embodimentsfor a ceramic ground shield 200 including the structure shown in FIG. 2with an electrically conductive layer 220, a first protective layer 222,and a second protective layer 224. FIG. 4A depicts one embodimentwherein electrically conductive layer 402 may be deposited on the uppersurface of plate 204. First protective layer 404 may be deposited onelectrically conductive layer 402. Second protective layer 406 may bedeposited on first protective layer 404. FIG. 4B depicts an alternativeembodiment wherein electrically conductive layer 402 may be deposited onthe upper surface of plate 204, edge interior wall 208, and edge uppersurface 210. First protective layer 404 may be deposited on electricallyconductive layer 402. Second protective layer 406 may be deposited onfirst protective layer 404. FIG. 4C depicts another alternativeembodiment wherein electrically conductive layer 402 may be deposited onthe upper surface of plate 204 and interior wall 216 of hollow shaft214. First protective layer 404 may be deposited on electricallyconductive layer 402. Second protective layer 406 may be deposited onfirst protective layer 404. FIG. 4D depicts another alternativeembodiment wherein electrically conductive layer 402 may be deposited onthe upper surface of plate 204, edge interior wall 208, edge uppersurface 210, edge exterior wall 212, the lower surface of plate 204, andexterior wall 218 of hollow shaft 214. First protective layer 404 may bedeposited on electrically conductive layer 402. Second protective layer406 may be deposited on first protective layer 404. In all embodimentsdescribed above, a third protective layer (not shown) may be depositedon second protective layer 406.

In further embodiments, electrically conductive layer 402, firstprotective layer 404, and second protective layer 406 may completelycover each surface of the ground shield or may cover edge exterior wall212 and/or the lower surface of plate 204 in addition to any of thesurfaces of ground shield 200 that these layers are shown to cover inthe illustrated examples. In further embodiments, electricallyconductive layer 402 may cover any of the surfaces of ground shield 200shown, but first protective layer 404 and second protective layer 406may completely cover each surface of ground shield 200 or,alternatively, may cover edge exterior wall 212 and/or the lower surfaceof plate 204 in addition to any surfaces of ground shield 200 that firstprotective layer 404 and second protective layer 406 are shown to coverin the illustrated examples. In further embodiments, electricallyconductive layer 402 and first protective layer 404 may cover any of thesurfaces of ground shield 200 shown, but second protective layer 406 maycompletely cover each surface of ground shield 200 or may alternativelycover edge exterior wall 212 and/or the lower surface of plate 204 inaddition to any surfaces of ground shield 200 that second protectivelayer 406 is shown to cover in the illustrated examples.

In any of the embodiments depicted in FIGS. 4A-4D, first protectivelayer 404 and/or second protective layer 406 may completely coverelectrically conductive layer 402 so that electrically conductive layer402 may not be exposed in the processing environment depicted in FIG. 1. This allows electrically conductive layer 402 to avoid corrosion inthe presence of plasma high oxidation and/or corrosive environment.Additionally, in any of the embodiments depicted in FIGS. 4A-4D, firstprotective layer 404 and/or second protective layer 406 may be depositedon surfaces of ground shield 200 that do not include electricallyconductive layer 402. For example, electrically conductive layer 402 maybe deposited on the upper surface of plate 204 and first protectivelayer 404 may be deposited on electrically conductive layer 402 and edgeinterior wall 208. Additionally, second protective layer 406 may bedeposited on first protective layer 404, edge interior wall 208, and mayalso be deposited on additional surfaces of ground shield 200.

In another embodiment not shown, ground shield 200 may be composed of aceramic material. An electrically conductive layer 402 may be depositedonto the upper surface of plate 204, edge interior wall 208, edge uppersurface 210, and edge exterior wall 212. A first protective layer 404may be deposited on electrically conductive layer 402. A secondprotective layer 406 may be deposited onto first protective layer 404.In a further embodiment, electrically conductive layer 402 may also bedeposited onto the lower surface of plate 204. First protective layer404 may be deposited on electrically conductive layer 402. Secondprotective layer 406 may be deposited on first protective layer 404.

FIGS. 5A-5E illustrate cross sectional side views of various embodimentsfor an electrically conductive ground shield 200 including the structureshown in FIG. 2 with first protective layer 222 and second protectivelayer 224. FIG. 5A depicts one embodiment wherein first protective layer502 may be deposited on the upper surface of plate 204. Secondprotective layer 504 may be deposited on first protective layer 502.FIG. 5B depicts an alternative embodiment wherein first protective layer502 may be deposited on the upper surface of plate 204, edge interiorwall 208, and edge upper surface 210. Second protective layer 504 may bedeposited on first protective layer 502. FIG. 5C depicts anotheralternative embodiment wherein first protective layer 502 may bedeposited on the upper surface of plate 204 and interior wall 216 ofhollow shaft 214. Second protective layer 504 may be deposited on firstprotective layer 502. FIG. 5D depicts another alternative embodimentwherein first protective layer 502 may be deposited on the upper surfaceof plate 204, edge interior wall 208, edge upper surface 210, edgeexterior wall 212, the lower surface of plate 204, and exterior wall 218of hollow shaft 214. Second protective layer 504 may be deposited onfirst protective layer 502. FIG. 5E depicts another alternativeembodiment wherein first protective layer 502 may be deposited on allsurfaces of ground shield 200. Second protective layer 504 may bedeposited on first protective layer 502. First protective layer 502and/or second protective layer 504 may be deposited on all surfaces ofground shield 200, so to avoid the exposure to the processingenvironment depicted in FIG. 1 . This allows the ground shield 200 toavoid corrosion in the presence of a high oxidation and/or corrosiveenvironment. In all embodiments described above, a third protectivelayer (not shown) may be deposited on second protective layer 504.

In further embodiments, first protective layer 502 and second protectivelayer 504 may completely cover the surfaces of ground shield 200 or maycover edge exterior wall 212 and/or the lower surface of plate 204, inaddition to any surfaces of ground shield 200 that these layers areshown to cover in the illustrated examples. In further embodiments,first protective layer 502 may cover any surface of ground shield 200shown, but second protective layer 504 may cover edge exterior wall 212and/or the lower surface of plate 204 in addition to any surface ofground shield 200 that second protective layer 504 is shown to cover inthe illustrated examples.

In any of the embodiments depicted in FIGS. 5A-5E, second protectivelayer 504 may be deposited on any surface of ground shield 200 that isnot covered by first protective layer 502. For example, first protectivelayer 502 may be deposited on the upper surface of plate 204 and secondprotective layer 504 may be deposited on first protective layer 502 andedge interior wall 208.

In another embodiment not shown, ground shield 200 may be composed of anelectrically conductive material. First protective layer 502 may bedeposited on the upper surface of plate 204, edge interior wall 208,edge upper surface 210, and edge exterior wall 212. Second protectivelayer 504 may be deposited on first protective layer 502. In a furtherembodiment, first protective layer 502 may be also deposited on thelower surface of plate 204. Second protective layer 504 may be depositedon first protective layer 502. First protective layer 502 and/or secondprotective layer 504 may be deposited on all surfaces of ground shield200, so to avoid the exposure to the processing environment of theprocessing chamber depicted in FIG. 1 . This allows ground shield 200 toavoid corrosion in the presence of a high oxidation and/or corrosiveenvironment.

FIG. 6 illustrates a cross sectional side view of one embodiment for aceramic ground shield 200, wherein a plurality of holes 608 may bedrilled through a plate 204 and may be filled with an electricallyconductive plug 610. Electrically conductive plug 610 may provide anelectrically conductive path for an RF signal.

Electrically conductive plug 610 may have a composition of one or moreof Mo, W, Ta, Hastelloy®, Inconel®, ITO, or another electricallyconductive material. An electrically conductive layer 602 may bedeposited on the upper surface of plate 204 and the surface ofelectrically conductive plug 610. First protective layer 604 may bedeposited on electrically conductive layer 602. Second protective layer606 may be deposited onto first protective layer 604. First protectivelayer 604 may have the composition of any ceramic materials describedherein. Similarly, second protective layer 606 may have the compositionof any ceramic material previously described herein. In alternativeembodiments, first protective layer 604 and/or second protective layer606 may cover additional surfaces of ground shield 200. For example,first protective layer 604 and/or second protective layer 606 may bedeposited on at least one of edge interior wall 208, edge upper surface210, edge exterior wall 212, the lower surface of plate 204, interiorwall 216 of hollow shaft 214, and exterior wall 218 of hollow shaft 214.

FIG. 7 illustrates a first process 700 for forming a ground shield. Atblock 702, a ceramic ground shield body is provided. The providedceramic ground shield body may be a plate and a raised edge extendingfrom an upper surface of the plate. The raised edge may include an edgeinterior wall, an edge upper surface, and an edge exterior wall. Theground shield body may further include a hollow shaft that includes aninterior wall and an exterior wall. In one embodiment, the ceramicground shield body is manufactured by performing sintering on a greenbody approximately having a target size and shape. After the sinteringprocess, the sintered ceramic body may be mechanically processed toachieve target dimensions with a higher degree of accuracy. In oneembodiment, the ground shield body may be composed of two or threeseparate components. These components may be sintered and furtherprocessed separately. Alternatively, one or more of the components maynot be sintered ceramic materials (e.g., may be metal such as stainlesssteel). For example, a ground shield plate may be a sintered ceramic anda shaft of the ground shield may be stainless steel or another metal.

At block 704, a plurality of holes may be drilled though a plate of theground shield body. At block 706, the plurality of holes may be filledwith a plurality of electrically conductive plugs. The electricallyconductive plugs may connect to leads at the lower surface of the plate,and the leads may connect to ground.

At block 708, at least the upper surface of the ground shield body maybe roughened. Roughness on the upper surface of the ground shield bodymay be achieved through the use of a bead blaster. A bead blaster may bea bead blasting cabinet, a hand held bead blaster, an automatic beadblaster, or any other type of bead blaster. In alternative embodiments,roughness on the upper surface of the ground shield body may be achievedthrough the use of a motorized abrasive pad. The upper surface of theground shield body (e.g., the upper surface of the plate) may beroughened to a target roughness of between about 0.10 microns to about6.00 microns. This may improve adhesion of an electrically conductivelayer and/or of a first protective layer to the ground shield body. Forexample, adhesion of plasma sprayed coatings may be improved by firstroughening the surface of the ground shield body.

At block 710, an electrically conductive layer may be deposited on atleast the upper surface of the ground shield body. The electricallyconductive layer may be composed of any electrically conductive materialdescribed herein. The electrically conductive layer may be deposited bytraditional atmospheric plasma spray, LPPS, VPS, screen printing, wetchemical deposition (e.g., sol gel), PVD, CVD, aerosol deposition,evaporation, ALD, PECVD, IAD, ion plating, immersion coating,sputtering, thermal spraying, hot isostatic pressing, cold isostaticpressing, lamination, compression molding, casting, compacting,sintering or co-sintering techniques.

At block 712, a first protective layer may be deposited on theelectrically conductive layer. The first protective layer may becomposed of any ceramic material described herein. The first protectivelayer may be deposited by traditional atmospheric plasma spray, LPPS,VPS, screen printing, wet chemical deposition (e.g., sol gel), CVD, PVD,aerosol deposition, evaporation PECVD, ion assisted deposition, ionplating, and their combinations. If the electrically conductive layer isdeposited using techniques such as PVD, CVD, ALD, PECVD or IAD, forexample, then the electrically conductive layer may be a conformal layerand the surface of the electrically conductive layer may haveapproximately the roughness of the underlying ground shield body (e.g.,the target roughness of the surface of the ground shield body).Accordingly, if the first protective layer is deposited, for example, byplasma spray or aerosol deposition, then the surface roughness of theelectrically conductive layer may improve adhesion of the firstprotective layer to the electrically conductive layer.

At block 714, the surface of the ground shield body covered by the firstprotective layer may be polished. Polishing may be performed by agrinder or CMP machine, for example. The first protective layer may bepolished to an average surface roughness of between about 0.10 micronsto about 2.00 microns.

At block 716, a second protective layer may be deposited on the firstprotective layer. The second protective layer may be composed of anyceramic material described herein. The second protective layer may bedeposited by traditional atmospheric plasma spray, LPPS, VPS, screenprinting, wet chemical deposition (e.g., sol gel), PVD, CVD, ALD,aerosol deposition, evaporation, ALD, PECVD, IAD, ion plating, immersioncoating, sputtering, thermal spraying, hot isostatic pressing, coldisostatic pressing, lamination, compression molding, casting,compacting, sintering or co-sintering techniques. In one embodiment, thesecond protective layer maybe deposited by a non-line-of-site depositiontechnique such as ALD or CVD, plasma immersion ion deposition (PIID),wet chemical deposition (e.g., sol gel), or plating. In one embodiment,the second protective layer may be a conformal protective layer with aporosity of approximately zero that seals any cracks and/or pores in thefirst protective layer.

At block 718, a third protective layer may be deposited on the secondprotective layer. The third protective layer may be composed of anyceramic material described herein. The third protective layer may bedeposited by traditional atmospheric plasma spray, LPPS, VPS, screenprinting, wet chemical deposition (e.g., sol gel), PVD, CVD, ALD,aerosol deposition, evaporation, ALD, PECVD, IAD, ion plating, immersioncoating, sputtering, thermal spraying, hot isostatic pressing, coldisostatic pressing, lamination, compression molding, casting,compacting, sintering or co-sintering techniques.

If the ground shield body may be composed of multiple differentcomponents, then some or all of one or more of the components may havebeen coated with the electrically conductive layer, the first protectivelayer, the second protective layer and/or the third protective layer.Subsequently, the multiple components may be assembled. For example, twohalves of a ground shield shaft may be attached together around a heatershaft 154B, and the combined halves of the ground shield shaft may beattached to a ground shield plate encircling the heater 150.

FIG. 8 illustrates a second process 800 for forming a ground shield. Atblock 802, an electrically conductive ground shield body is provided.The provided electrically conductive ground shield body may include aplate and a raised edge extending from an upper surface of the plate.The raised edge may include an edge interior wall, an edge uppersurface, and an edge exterior wall. The ground shield body may furtherinclude a hollow shaft that includes an interior wall and an exteriorwall. The electrically conductive ground shield body may be formed byany of the electrically conductive materials described herein for theground shield body. In one embodiment, the surface of the ground shieldbody is roughened (e.g., such as by bead blasting).

At block 804, a first protective layer may be deposited on at least theupper surface of the ground shield body. The first protective layer maybe composed of any ceramic material described herein. The firstprotective layer may be deposited by traditional atmospheric plasmaspray, LPPS, VPS, screen printing, wet chemical deposition (e.g., solgel), PVD, CVD, ALD, aerosol deposition, evaporation, PECVD, IAD, ionplating, immersion coating, sputtering, thermal spraying, hot isostaticpressing, cold isostatic pressing, lamination, compression molding,casting, compacting, sintering or co-sintering techniques.

At block 806, the surface of the ground shield body covered by the firstprotective layer may be polished.

At block 808, a second protective layer may be deposited on the firstprotective layer. The second protective layer may be composed of anyceramic material described herein. The second protective layer may bedeposited by traditional atmospheric plasma spray, LPPS, VPS, screenprinting, wet chemical deposition (e.g., sol gel), PVD, CVD, ALD,aerosol deposition, evaporation, ALD, PECVD, IAD, ion plating, immersioncoating, sputtering, thermal spraying, hot isostatic pressing, coldisostatic pressing, lamination, compression molding, casting,compacting, sintering or co-sintering techniques. In one embodiment, thesecond protective layer is deposited by a non-line-of-site depositiontechnique such as ALD or CVD, plasma immersion ion deposition (PIID),wet chemical deposition, or plating

At block 810, a third protective layer may be deposited on the secondprotective layer. The third protective layer may be composed of anyceramic material described herein. The third protective layer may bedeposited by traditional atmospheric plasma spray, LPPS, VPS, screenprinting, wet chemical deposition (e.g., sol gel), PVD, CVD, ALD,aerosol deposition, evaporation, ALD, PECVD, IAD, ion plating, immersioncoating, sputtering, thermal spraying, hot isostatic pressing, coldisostatic pressing, lamination, compression molding, casting,compacting, sintering or co-sintering techniques.

The preceding description sets forth numerous specific details such asexamples of specific systems, components, methods, and so forth, inorder to provide a good understanding of several embodiments of thepresent disclosure. It will be apparent to one skilled in the art,however, that at least some embodiments of the present disclosure may bepracticed without these specific details. In other instances, well-knowncomponents or methods are not described in detail or are presented insimple block diagram format in order to avoid unnecessarily obscuringthe present disclosure. Thus, the specific details set forth are merelyexemplary. Particular implementations may vary from these exemplarydetails and still be contemplated to be within the scope of the presentdisclosure.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, the appearances of the phrase “in oneembodiment” or “in an embodiment” in various places throughout thisspecification are not necessarily all referring to the same embodiment.In addition, the term “or” is intended to mean an inclusive “or” ratherthan an exclusive “or.” When the term “about” or “approximately” is usedherein, this is intended to mean that the nominal value presented isprecise within ±10%.

Although the operations of the methods herein are shown and described ina particular order, the order of operations of each method may bealtered so that certain operations may be performed in an inverse orderor so that certain operation may be performed, at least in part,concurrently with other operations. In another embodiment, instructionsor sub-operations of distinct operations may be in an intermittentand/or alternating manner. In one embodiment, multiple metal bondingoperations are performed as a single step.

It is understood that the above description is intended to beillustrative, and not restrictive. Many other embodiments will beapparent to those of skill in the art upon reading and understanding theabove description. The scope of the disclosure should, therefore, bedetermined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled.

What is claimed is:
 1. A ground shield of a processing chamber,comprising: a ceramic body comprising a ground shield plate, a raisededge extending from an upper surface of the ground shield plate, and ahollow shaft that extends from a lower surface of the ground shieldplate; an electrically conductive layer deposited on and conforming toat least the upper surface of the ground shield plate and at least anedge upper surface of the raised edge, wherein the electricallyconductive layer is connected to ground at one or more points; and afirst protective layer deposited on at least the electrically conductivelayer, wherein a heater plate of a heater fits within the raised edgeand on the ground shield plate such that the heater plate is disposed ontop of the first protective layer, the electrically conductive layer,and the upper surface of the ground shield plate, and wherein the groundshield is to reduce at least one of a parasitic capacitance or aparasitic inductance of the heater associated with a process performedat the processing chamber.
 2. The ground shield of claim 1, furthercomprising: a second protective layer deposited on the first protectivelayer, wherein the second protective layer is conformal, has a thicknessof approximately 50.00 nm-2.00 mm, and has a porosity of less than 0.1%.3. The ground shield of claim 2, wherein the second protective layercomprises at least one yttrium oxide, erbium oxide, tantalum oxide,yttrium fluoride, alumina, aluminum fluoride, zirconium dioxide, aY₂O₃—ZrO₂ solid solution, a material comprising Y₄Al₂O₉ and a Y₂O₃—ZrO₂solid solution, or a combination thereof.
 4. The ground shield of claim2 wherein the raised edge further comprises an edge interior wall and anedge exterior wall, and wherein the electrically conductive layer andthe first protective layer further conform to the edge interior wall andthe edge exterior wall.
 5. The ground shield of claim 4, wherein atleast one of the electrically conductive layer, the first protectivelayer, or the second protective layer further covers a lower surface ofthe ground shield plate, an interior wall of the hollow shaft and anexterior wall of the hollow shaft.
 6. The ground shield of claim 2,wherein at least one of the electrically conductive layer, the firstprotective layer, or the second protective layer further covers aninterior wall of the hollow shaft.
 7. The ground shield of claim 1,wherein the first protective layer comprises at least one of alumina,Y₂SiO₅, Y₂Si₂O₇, Y₅O₄F₇, tantalum, silicon carbide, yttria, erbiumoxide, a Y₂O₃—ZrO₂ solid solution, a material comprising Y₄Al₂O₉ and aY₂O₃—ZrO₂ solid solution, or a combination thereof.
 8. The ground shieldof claim 1, wherein the first protective layer has a thickness ofapproximately 1.00 μm-2.00 mm, and has a porosity of 0.1-10.0%.
 9. Theground shield of claim 1, wherein the ceramic body further comprises aplurality of holes drilled into the ground shield plate, and wherein oneor more of the plurality of holes are filled with an electricallyconductive plug.
 10. The ground shield of claim 1, wherein: the ceramicbody comprises at least one of alumina, aluminum nitride, silicon,silicon carbide, or silicon nitride; and the electrically conductivelayer comprises at least one of molybdenum, tungsten, nickel, tantalum,an alloy comprising nickel, molybdenum, titanium, and chromium, an alloycomprising nickel, chromium and iron, or indium tin oxide.
 11. Theground shield of claim 1, wherein the ceramic body has a firstcoefficient of thermal expansion (CTE) and the first protective layerhas a second CTE, wherein the second CTE is within 2.5×10⁻⁶/° C. of thefirst CTE.
 12. A substrate support assembly of a processing chamber,comprising: a heater comprising a heater plate; and a ground shieldcomprising a disc-shaped ceramic body and a ground shield shaft thatextends from a lower surface of the disc-shaped ceramic body, wherein anupper surface of the disc-shaped ceramic body comprises a raised edgeextending from an upper surface of the disc-shaped ceramic body, theground shield further comprising: an electrically conductive layerdeposited on and conforming to at least the upper surface of thedisc-shaped ceramic body and at least an edge upper surface of theraised edge, wherein the electrically conductive layer is connected toground at one or more points; and a first protective layer deposited onat least the electrically conductive layer, wherein the heater plate ofthe heater fits within the raised edge and on the disc-shaped ceramicbody such that the heater plate is disposed on top of the firstprotective layer, the electrically conductive layer, and the uppersurface of the disc-shaped ceramic body, and wherein the ground shieldis configured to reduce at least one of a parasitic capacitance or aparasitic inductance of the heater associated with a process performedat the processing chamber.
 13. The substrate support assembly of claim12, further comprising a second protective layer deposited on the firstprotective layer, wherein the second protective layer is a conformallayer, has a thickness of approximately 50.00 nm-2.00 mm, has a porosityof less than 0.1%, and comprises at least one of yttrium oxide, erbiumoxide, tantalum oxide, yttrium fluoride, alumina, aluminum fluoride,zirconium dioxide, a Y₂O₃—ZrO₂ solid solution, a material comprisingY₄Al₂O₉ and a Y₂O₃—ZrO₂ solid solution, or a combination thereof. 14.The substrate support assembly of claim 13, wherein the raised edgefurther comprises an edge interior wall and an edge exterior wall, andwherein the electrically conductive layer and the first protective layerfurther conform to the edge interior wall, and the edge exterior wall.15. The substrate support assembly of claim 14, wherein at least one ofthe electrically conductive layer, the first protective layer, or thesecond protective layer further covers either an exterior wall of ahollow shaft or an interior wall of the hollow shaft.
 16. The substratesupport assembly of claim 12, wherein the first protective layer has athickness of approximately 1.00 μm-2.00 mm, has a porosity of less than6%, and comprises at least one of alumina, Y₂SiO₅, Y₂Si₂O₇, Y₅O₄F₇,tantalum oxide, yttrium fluoride, alumina, aluminum fluoride, zirconiumdioxide, a Y₂O₃—ZrO₂ solid solution, a material comprising Y₄Al₂O₉ and aY₂O₃—ZrO₂ solid solution, or a combination thereof.
 17. A ground shieldof a processing chamber, comprising: an electrically conductive bodycomprising a ground shield plate and a raised edge extending from anupper surface of the ground shield plate wherein the electricallyconductive body is connected to ground at one or more points and whereinthe raised edge comprises an edge interior wall, an edge upper surfaceand an edge exterior wall; a first protective layer conforming to atleast the upper surface of the ground shield plate and the edge interiorwall, the edge upper surface, and the edge exterior wall of the raisededge, wherein the first protective layer has a thickness ofapproximately 1.00 μm-2.00 mm, has a porosity of 0.1-10.0%, andcomprises at least one of alumina, Y₂SiO₅, Y₂Si₂O₇, Y₅O₄F₇, tantalum,silicon carbide, yttria, erbium oxide, a Y₂O₃—ZrO₂ solid solution, amaterial comprising Y₄Al₂O₉ and a Y₂O₃—ZrO₂ solid solution, or acombination thereof; and a second protective layer on at least the firstprotective layer, wherein the second protective layer is a conformallayer, has a thickness of approximately 50.00 nm-5.00 μm, has a porosityof less than 0.1%, and comprises at least one of yttrium oxide, erbiumoxide, tantalum oxide, yttrium fluoride, alumina, aluminum fluoride,zirconium dioxide a Y₂O₃—ZrO₂ solid solution, a material comprisingY₄Al₂O₉ and a Y₂O₃—ZrO₂ solid solution, or a combination thereof, andwherein a heater plate of a heater fits within the raised edge and onthe ground shield plate such that the heater plate is disposed on top ofthe second protective layer, the first protective layer, and the uppersurface of the ground shield plate, and wherein the ground shield is toreduce at least one of a parasitic capacitance or a parasitic inductanceof the heater associated with a process performed at the processingchamber.
 18. The ground shield of claim 17, wherein the electricallyconductive body has a first CTE and the first protective layer has asecond CTE, wherein the second CTE is the same as the first CTE.
 19. Theground shield of claim 17 wherein the electrically conductive body has afirst CTE and the first protective layer has a second CTE, wherein thesecond CTE is within 2.5×10⁻⁶/° C. of the first CTE.
 20. The groundshield of claim 17, further comprising a hollow shaft that extends froma lower surface of the ground shield plate, wherein at least one of thefirst protective layer or the second protective layer further covers atleast one of an exterior wall of a hollow shaft or an interior wall ofthe hollow shaft.